Finding good-fitting rubber parts for the Mangusta seems to remain a hit/miss project for everyone (especially for the rear!!) so thought I'd post at least one find that appears like a good replacement. My original engine cover bumpers were mostly destroyed on removal b/c of corrosion on the M5 threads, and there is nothing to 'grab' except the rubber portions, which quickly tear. These new bumpers have an appropriate 19mm OD, and will need trimming to length (all cars will probably be a bit different...and for that matter all four corners could be different) but the16mm height should be tall enough for all locations.
Fairly easy to Google sources for this specific part, but finding similar bumpers from a different manufacturer has been fruitless. I never discovered the original source for Mangusta 'wing' bumpers (Fiat/Lancia/etc?) and have abandoned that approach finally